In digital communications or data transmission systems it is known to apply time interleaving or subslicing to combat the effects of time selective fading or the influence of noise bursts. One aspect of time selective fading is the so-called fast fading, which is caused by multipath propagation. The signals of the different paths from a transmitter (or from multiple transmitters of, for instance, OFDM Single Frequency Networks), superimpose each other in amplitude and phase. As especially the phase varies over the frequencies, this causes a frequency selective channel. Therefore, the frequencies at the receiver (i.e. related OFDM sub-carriers) have different reception amplitudes.
Additionally, the amplitude and the phase of the different reception paths also depend on the position of the receiver. In case of a moving receiver, especially the phase of the signals of the different reception paths changes, which causes a time selective channel. The changes in the time direction can also have a very regular structure. The change rate of this structure over the time axis is proportional to the relative velocity of the receiver to the transmitter(s) and the transmission frequency of the signal. Also other disturbances, such as impulsive noise, can have a regular structure, e.g. caused by the line cycle frequency of the power grid or by bursts from other data transmission systems, e.g. a GSM communications system.
Any digital data transmission systems, such as systems in accordance with the DVB-T2 standard (second generation digital terrestrial television broadcasting systems standard), use a framing structure with time interleaving and/or sub-slicing that applies a regular structure in time domain. This frame structure is generally built by a frame builder, i.e. an apparatus for mapping error correction code encoded time-domain data of at least two mapping input data streams onto a time-domain mapping output data stream.